The Atmosphere

This is a hostile place for humans - both temperature and a lack of pressure pose the biggest threat.

The earth's atmosphere is divided into 5 layers. We live in the
troposhere. Felix jumped from the stratosphere.

Air pressure is nearly nonexistent at Felix's jump altitude of
128,100 feet - this means 99% of the earth's atmosphere was out of
reach. Normally the atmosphere cools a few degrees with a rise in
altitude. Flying a jet at about 35,000 ft is typically where
temperatures drop off dramatically to -50F or even -70F
degrees.

The cooling trend slows down as you enter the initial layer of
the stratosphere, which is never at an exact altitude. The
stratosphere just like any layer of the atmosphere starts and stops
at various heights depending on where you are on the planet. These
layers are temperature dependent. So Bobby McGee at the equator
will give a report on the altitude of the stratosphere which will
differ from Jenny McGoo's report because she lives at the North
Pole. These variations change with the seasons
too.

So the reason the temperature actually increases as you climb
through the stratosphere is due to the ozone layer. Ozone molecules
absorb energy and give heat back to the stratosphere. Still, it's
very cold: 0 to -10F degrees.